Question

What two types of icmp messages are received at the sending host executing the traceroute program?

Answer 1

Well to know the route  from a one particular host to another host traceroute serve the advantage to trace.

It is also helpful when it comes to knowing the names and address of the routers.

ttl is received at the sending host which then executes the traceroute..

These are the two types of icmp messages are received at the sending host.